The present invention relates to a novel polypeptide, a DNA sequence coding for the same and a use thereof.
Many cell growth factors have been isolated and their structures have been elucidated since the discovery of epidermal growth factor (hereinafter referred to as EGF) and nerve growth factor (hereinafter referred to as NGF).
Cell growth factors are useful for the elucidation of the mechanism of cell differentiation and cell multiplication mechanism, and some of them, including human EGF, are expected to be useful as drugs. Accordingly, studies thereon have become increasingly prevalent in recent years.
Although the human NGF gene have been isolated, there has been no reports concerning the production of human NGF in large amounts by use of recombinant DNA techniques.
If a novel polypeptide promoting the growth of animal cells is obtained, new investigations can be made thereby. Such novel polypeptides having activities similar to known growth factors may also be utilized as drugs.
For the purpose of discovering such a novel peptide, the present inventors used a DNA sequence encoding NGF as a probe and cloned a DNA sequence hybridizable therewith from cDNA libraries of a human glibma. As a result, the inventors succeeded in obtaining a DNA (cDNA) sequence coding for a novel polypeptide. The cDNA of the present invention may be expressed in a host cell to produce the novel polypeptide. This polypeptide may further be used as a reagent for studies relating to the differentiation, growth and survival of animal cells. The polypeptide may further be used as a drug. The present inventors have made further investigations, based on the information described above, and consequently completed this invention.
It is therefore an object of the present invention to provide a novel polypeptide useful as a reagent for research investigations or as a drug. Other objects will be apparent from the following description and appended drawings.
The present invention provides:
(1) a polypeptide (I) including the following amino acid sequence (II) in a molecule thereof:
(this amino acid sequence is hereinafter also referred to as formula [II] for brevity),
(2) a DNA coding for the polypeptide described in (1),
(3) a vector including the DNA sequence described in (2),
(4) a transformant transformed by the vector described in (3), and
(5) a process for producing the polypeptide (I) which comprises cultivating the transformant described in (4) in a culture medium to produce and accumulate the polypeptide described in (1) in a culture.